1. 1 Spacecraft Thermal Design Introduction to Space Systems and Spacecraft Design Space Systems Design

2. 2 What are the conditions the spacecraft must face in space? Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design 1.What is the source of heating and cooling for a s/c in space? a)Sun, internal, earth, moon, other planets, atmospheric friction, micrometeorites b)Radiation to cooler environment – deep space, other components 2.How does the thermal conditions in space differ than on the ground? a)No natural air convection source to conduct heat to or from areas of the spacecraft b)Vacuum – extreme, fast temperature variations 3.What are the extremes that a spacecraft will see in space? a)Sunlight vs eclipse b)Operation extremes – Tx, Thrusters

3. 3 4.What is the range of temperatures that the s/c components can operate? a)-55C to 125C Military Specifications Introduction to Space Systems and Spacecraft Design Space Systems Design 5.Will the space environment change over time in space? a)Solar cycle, orbit changes due to perturbations & seasons Spacecraft Thermal Design

4. 4 1.Conduction and radiation Introduction to Space Systems and Spacecraft Design Space Systems Design 2.Spot electrical cooling with devices such as peltrier coolers. 3.Move heat from hot areas to cool areas by conduction, fluids and heat pipes. How is heat transferred in the space environment? Spacecraft Thermal Design

5. 5 Sources: (where heat comes from)Sinks: (where heat goes) Internally Introduction to Space Systems and Spacecraft Design Space Systems Design Space Environment Heat generated internally Spacecraft Thermal Design

6. 6 Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

7. 7 How will the s/c thermal requirements change with the operational scenario? Internal heat generation and dissipation Introduction to Space Systems and Spacecraft Design Space Systems Design 1.When transmitters are on 2.When thrusters are firing 3.When solar arrays are deployed 5.When spacecraft fuels are used 4.When satellite orientation is changed Spacecraft Thermal Design

8. 8 Conditions for s/c equipment Non operating temperature range Operating temperature ranges Switch-on temperature limit Design limits of the devices Hot and cold turn on Damage occur at extremes Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

9. 9 Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

10. 10 Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

11. 11 Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

12. 12 Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

13. Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

14. Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

15. 15 Effects of temperature ranges on components Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design Temperature Electronics Too Low Too High Permanent damage Operates out of design ranges Operates incorrectly Permanent damage Operates incorrectly Solar Arrays Upredictable Batteries Better efficiencyLower efficiency Effects of temperature ranges on components Temperature Electronics Too Low Too High Operates incorrectly Permanent damage Operates out of design ranges frequencies sensitivities Solar Arrays Better efficiency Lower efficiency Batteries Poor efficiency Better efficiency (to a point) Structures Too Low Differential Too High Stress components Excess stresses Stresses Poor efficiency Can’t charge Better efficiency (to a point) Stress components Too Low Differential Too High Structures Excess stressesStresses

16. 16 Thermal control of components Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design How do you control thermal conditions on a spacecraft? Thermal coatings on exterior Thermal coatings on interior Change passivity and emissivity of exterior surface of spacecraft Change to cool off or head up spacecraft exterior surfaces Move heat from subsystem boxes to other parts of spacecraft Move heat from interior components to boxes

17. 17 Methods of heat transfer Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design Convection Heat transferred by liquid or gas Conduction Heat transferred in a solid or non circulating fluid Radiation Heat transferred by electromagnetic waves

18. 18 Analysis Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design Conduction Q = in watts heat flow k = thermal conductivity (W*m -1 K -1 ) A = cross sectional area = m 2  x = path length – m T = temperature in K (273 + T 0 C)  A Q T2T2 T1T1 Q = (T 1 -T 2 ) watts/m 2 kA xx Q Assumes not loss from sides

19. 19 Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

20. 20 Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

21. 21 New materials? Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design What about nanotubes? What about diamonds? ????

22. 22 Q =   T 4 Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design Analysis Radiation Q = in watts heat flow /unit time /surface area  = emissivity  = Stefan-Boltzman’s constant 5.670 x 10-8 W*m -2 K -4 T = temperature in K (273 + T 0 C) Q T 

23. 23 Radiation Equilibrium Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

24. 24 Effects of Coatings Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

25. 25 Changing S/C temperatures by selection of exterior surface Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

26. 26 Changing S/C temperatures by selection of exterior surface Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

27. 27 Radiation when surface has transmissivity Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

28. 28 Radiation with surface like solar cells Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

29. 29 Active & Passive Systems Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

30. 30 Passive Heat Pipes Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

31. 31 Passive Heat Pipes Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

32. 32 Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

33. 33 Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

34. 34 Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

35. 35 Read section 11.5 from SMAD Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

36. 36 Thermal Control Components Surface Finishes Insulation Louvers Heat Pipes Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

37. 37 Design Considerations Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design

38. 38 Remember when doing thermal design for satellites, always keep your cool! Introduction to Space Systems and Spacecraft Design Space Systems Design Spacecraft Thermal Design